Hot-air furnace



Feb. 5, 1929. 1,700,911

w. 0. SMITH HOT AIR FURNACE Filed NOV. 12, 1927 gwueni w Patented Feb. 5, 1929.

UNITED STATES 1,Zfi0,9ll

PATENT QFFICE.

WILLIAM 0. SMITH, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR OF TWO-FIFTHS TO JOHN CLIFFORD YOUNG, OF PITTSBURGH, PENNSYLVANIA.

HOT-AIR Application filed November The invention relates to hot air furnaces.

The object of the present invention is to improve the construction of hot air furnaces and to provide a simple. practical and efficient hot air furnace of comparatively inexpensive c mstruction. adapted to reduce the consumption of fuel and to increase the heating effect materially, and equipped with means for increasing" the heating effect of any hot air conduit which may be found to be weak and below the heating capacity of the other hot air conduits. In practice. with hot air furnaces it is often the case that at least one of the hot air conduits is weak and does not supply an amount of hot air equal. to that supplied by the other conduits. and the hood attachment of the present invention is for the purpose of assisting such weak pipe or pipes and of enabling the same to supply the required amount of hot air.

Also in the present day furnaces having inner and outer shells surrounding the fire box there is considerable space between the inner shell and the fire box, and also in constructions where no inner shell is employed, there is also considerable space between the outer shell and the tire box.

It is an object of the present invention to cut down the possibility of cold air coming up through the radiator when there is a. low fire by arranging an inner shell in close proximity to the radiator and surrounding the fire box and connecting the cold air intakes with the narrow space between the inner shell and the fire box, so that the cold air will be thoroughly subjected to the heating effect of the tire box before passing upward to the Zone of the radiator.

With these and other objects in view, the invention consists in the construction and novel combination and arrangement of parts hereinafter fully described, illustrated in the accompanying drawings and pointed out in the claims hereto appended. it being understood that various changes in the form, proportion and minor details of construction, within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings:

Figure 1 is a vertical sectional view of a hot air furnace constructed in accordance with this invention;

Fig. 2 is a plan view partly in section illus FURNACE.

12, 1927. Serial No. 232,900.

trating the arrangement of the auxiliary hood.

In the accompanying drawings in which is illustrated the preferred embodiment of the invention. the hot air furnace comprises in its construction a tire box 1 having the fuel feed door 2 and surmounting an ash pit 2} having an ash pit door 4 of the usual construction. The fire box, which is arranged within an outer shell 5 is surroumled at its lower and intermediate portions by an inner shell 6 arranged in close proximity to the tire box and conforming to the contour of the same and forming a narrow intervening space 7 between the inner shell (3 and the tire box for the passage of the cold air entering the furnace. One or more cold air intakes 8 may be employed and they extend to the inner shell 6 and communicate at their iner ends with the intervening space 7 between the inner shell and the fire box. The inner shell extends upward to wi hin a short distance of the radiator 9 of the furnace to permit heated air in the space between the inner and outer shells to pass upward through the space between the radiator and the top of the fire box.

The radiator is connected with the tire box in the usual manner and forms a passage for the products of combustion; and as the particular construction of the radiator and the means for providing passages for the products of combustion does not constitute a portion of the present improvements, and as any preferred construe-tum of such means may be employed, illustration and description of such particular means and construc tion are deemed unnecessary. The radiator is spaced from the upper portion of the tire box and from the upper end of the inner shell and the hot air conduits 10 are connected with the upper portion of the outer shell in the usual manner and are designed to extend to the various points to be supplied with hot air.

it has been found by experience with hot air furnaces that usually one or more of the conduits 10 of a hot air furnace are found to be weak and unable to supply the required amount of hot air, and in order to remedy this defect and enable all of the hot air conduits to supply the full amount of hot air required, the furnace is equipped with one or more auxiliary hoods 11, which are open at the bottom and whicl are supported upon the crown of the tire box and upon the radiator. The hood 11. has straight lower edges extending from the outer portion of the radiator to the fire box, and it is provided adjacent to the same with concave lower rear edges 12, which conform to the configuration of the said fire box. The hood is provided at the front or outer portion .of the radiator with an attaching flange 13 which may be L-shaped or partially hook shaped and secured to the radiator at the top and outer side thereof by suitable fastening devices It and 15. The outer or front side of the attaching portion and fastening device 15 may, if desired, be omitted, and various means may be employed for securing the hood 11 to the furnace. The hood has a tubular inclined outer portion 16 extending upwardly and outwardly and preferably terminating within a short distance of the inner end of the hot air conduit to be assisted. A space of about two inches has been found to be most advantageous, and the passage of the hot air through the hood and into the adjacent registering hot air conduit 10 produces a suction which will draw heated air from the space surrounding the radiator into the hot air con duit 10. This will enable a weak hot air conduit to deliver the required amount of hot air and to feed the hot air with the same capacity as any of the other hot air conduits of the furnace. The hood provides a direct passage of heated air to the conduit 10 and produces a suction or draft through the hot air conduit associated With the hood.

What is claimed is:

1. In a hot air furnace, the combination of a fire box, a radiator surrounding the upper portion of the fire box, the top portion of the fire box projecting above the radiator, an outer casing receiving the fire box and the radiator, an inner shell surrounding the fire box and arranged in close proximity thereto to form a narrow intervening space between the inner shell and the fire box, said inner shell conforming to the configuration of the fire box and terminating short of the radiator to providea relatively small space between theupperedge of the inner shell and the radiator, and a cold air intake extending to the inner shell and communicating with a space between the same and the fire box.

2. In a hot air furnace, the con'ibination of a fire box, a radiator surrounding the upper portion of the tire box in spaced relation with the same. the top portion of the tire box projecting above the radiator, an outer casing, hot air conduits extending from the outer casing above the radiator, and an auxiliary hood associated with one of the hot air conduits and supported upon the projecting top of the tire box and the radiator, said auxiliary hood being open at the bottom and having a tubular outer portion extending to a point adjacent to and in line with the said hot air conduit and spaced from the same and from the outer casing to form a suction.

3. In a hot air furnace, the combination of a fire box. a radiator surrounding the upper portion of the tire box in spaced relation with the same, the top portion of the fire box projecting above the radiator, an outer casin hot air conduit extending from the outer casing above the radiator, and an auxiliary hood associated with one of the hot air conduits and supported upon the projecting top of the fire box and radiator, said auxiliary hood being provided at the front with an attaching flange conforming to the configuration of the radiator, and fastening means for securing the attaching means to the radiator.

In testimony whereof I have hereunto set my hand.

WILLIAM 0. SMITH. 

